Method of inspecting point-of-care biological test appliances

Background of the invention

The present invention relates to the general field of biological test appliances suitable for measuring or evaluating a biological variable at a point of care.

Such appliances are generally installed away from a laboratory, and frequently in an ambulatory service or even at a patient's home. Such appliances are generally portable, sometimes precalibrated, fast, and easy to use.

The invention applies more particularly to all point-of-care appliances for testing glycemia and it also applies to point-of-care testing of other biological parameters that can be measured by a biological test appliance at the point of care, i.e. away from a laboratory. Such parameters include blood gas, measuring hematocrits, measuring lactates, measuring urinary or blood ionograms, measuring urinary glucose, measuring uric acid, measuring cholesterol, measuring triglycerides, and any other physicochemical and/or biological parameter that is useful for diagnosis and decision making concerning the care to be given to a patient.

Depending on their construction, such point-of-care biological test appliances may operate continuously, or discretely.

The invention relates particularly to such point-of-care biological test appliances where it is useful or even essential to monitor their quality. Since such appliances are used in distinct places, sometimes on private premises, it is necessary to inspect that the values given by such appliances are correct.

At present, in order to inspect such a point-of-care biological test appliance, a measurement is performed by the appliance with the result of the measurement being sent to the laboratory, and simultaneously a venous blood sample is taken for sending to the laboratory as well as the measurement performed by the point-of-care biological test appliance.

A biologist then measures the biological value in the venous blood and compares the values that have been obtained in order to determine whether the point-of-care biological test appliance is functioning correctly or is functioning erroneously.

Insofar as point-of-care biological test appliances measuring glycemia generally use capillary blood, whereas the sample sent to the laboratory is venous blood, there is necessarily a bias between the values measured for those two types of blood.

This bias is made uncertain and is made greater by the fact that the test means are necessarily different and make use of different principles. Uncertainty concerning the real value of the bias gives rise to potential hazard if the point-of-care biological test appliance is declared valid when in fact the measurements it is making are significantly wrong. The inspection performed in that way can only be approximate and ultimately relies on the expertise of the biologist.

Nowadays another technique for inspecting a point-of-care biological test appliance exists and is recommended by the manufacturers of such appliances. Inspection is based on using a solution made available by the manufacturer for inspecting the point-of-care appliance.

Once the manufacturer has acquired a measurement for the solution, the value as measured is compared with ranges that are also supplied by the manufacturer.

This makes inspection direct, but it does not make it possible to evaluate the point-of-care biological test appliance relative to other appliances of other types and possibly operating on other principles.

It is also necessary to have a special control solution for each type of appliance in order to inspect all of the point-of-care biological test appliances in a group. That is difficult to implement and constitutes a source of error. It can therefore be harmful when several different types of point-of-care biological test appliance are in use by a given hospital service and when it is necessary to inspect their reliability and uniformity.

The invention thus proposes providing a method that supplements inspecting a point-of-care biological test appliance with the solution supplied by the manufacturer, and for this purpose the invention proposes an automatic technique that improves and simplifies inspection by performing measurements in parallel on the point-of-care biological test appliance and on a biological test appliance situated in a laboratory.

Object and summary of the invention

An object of the present invention is thus to mitigate the drawbacks presented by the two presently-known methods by proposing a method of inspecting point-of-care biological test appliances for on-site implementation using an "inspection" appliance, the method comprising the steps of:

a) on-site inputting or reception of qualitative data characterizing a point-of-care biological test appliance for inspection and characterizing the environment in which the appliance is to be found;

b) on-site inputting or reception of the value of a biological variable of a "control" solution as measured by the point-of-care biological test appliance for inspection;

c) acquiring the value of the biological variable of the control solution as measured by a reference biological test appliance;

d) transmitting the input or received value, the acquired value, and the input or received qualitative data to a centralizing computer system;

e) within the centralizing computer system, determining a bias that is to be expected between the input or received value of the biological variable and the value as measured by the reference appliance, the expected bias being determined as a function of the input or received qualitative data, including data relating to the environment in which the appliance is used, and of comparison data stored in the computer system;

f) comparing the value as measured by the point-of-care biological test appliance with the value as measured by the reference appliance while taking the bias into account;

g) storing comparison data relating to the comparison performed in the computer system, said comparison data being stored in association with the qualitative data;

h) within the computer system, generating a inspection report; and

i) sending the report to the inspection appliance or to a computer terminal associated with the inspection appliance.

Such a method makes it possible to automate inspecting the quality of point-of-care biological test appliances in the environments in which they are normally used with the help of an inspection appliance that is used for inspecting a plurality of point-of-care biological test appliances. The inspection appliance communicates with a centralizing computer system that is suitable for determining an appropriate bias, which bias might possibly differ for each inspection event.

In particular, the bias is determined in rational manner as a function of known qualitative data that is rationalized by inputting or receiving qualitative data encoded either in a numerical format or directly by the operator inputting codes, or by transforming the input from the operator into a numerical code.

The use of qualitative data qualifying the environment of the point-of-care biological test appliance for inspection also makes it possible to inspect point-of-care biological test appliances as a function of the environment in which they are used. The presence of such qualitative data also makes it possible, periodically, to inspect not only the state and the performance of point-of-care biological test appliances, but also the state of the consumables being used.

The method of the invention thus proposes making the use of point-of-care biological test appliances more secure by monitoring such equipment in a relatively continuous and uniform manner. It presents the advantage of making the results obtained by the point-of-care biological test appliances more uniform, or at least of providing elements for making comparisons between them. Knowledge of the bias that exists between the measurements made by appliances of different types is a major advantage since this makes it possible to take the bias directly into account when performing a comparison. The comparison then makes use directly of an expected target value as calculated from the bias and from the value measured on the reference appliance and received from the inspection appliance. According to the invention, the bias is determined and applied as a function of the situations observed and summarized in the qualitative data relating to the environment of point-of-care biological test appliance. This serves to make the operator's expertise more pertinent.

The expertise of the biologist then applies to defining all of the particular environmental and utilization conditions of any kind that may harm the quality of the results obtained in the particular context of use outside the laboratory.

The role of the biologist is to propose "questionnaires" organized to qualify these particular conditions of use in care establishments. These conditions are then compared with the initial recommendations of the manufacturers of the equipment used.

More generally, since the measurements performed by point-of-care biological test appliances are subject to inspection, the method serves to make more secure any medical acts that are performed as a function of such analyses.

Furthermore, the invention makes it possible to take account of the environment in which the point-of-care biological test appliance is used, and this can be very useful. The variability of the environment in which point-of-care tests are made can have so much influence on the results obtained as to make this practice dangerous. For example, a dirty glycemia reader can constitute a major vector for nosocomial infection, regardless of any potential disturbance to its results.

A detailed survey of the utilization environments in association with the differences in the results obtained from known solutions serves to enable a biologist: to continuously redefine the limits in which point-of-care biological test appliances should be used, including appliances that are used at home (home tests) or in doctors' surgeries (doctors tests) in the daily clinical practice of care establishments, or at any other utilization site; and to supplement user training or to take an appliance out of service, where appropriate, when the accurate observation of the circumstances of use of the equipment and the results obtained show that the limits of the method have been reached and that the level of risk is out of all proportion when the appliances are used outside the "secure" context of a medical test laboratory.

On receiving the report, the inspection appliance, assuming it is bidirectional, becomes a platform for monitoring the inspection process, all the way from inputting data to obtaining the result.

In other embodiments, the report is sent to a computer terminal, e.g. situated close to the inspection appliance or in premises, e.g. in a hospital, dedicated to centralized inspection of point-of-care biological test appliances. The computer terminal is associated with the inspection appliances in that it receives the reports relating to the point-of-care biological test appliances previously inspected by the inspection appliances.

In a preferred embodiment of the invention, the inspection appliance is a reference biological test appliance on which the value of the biological variable of the control solution is measured directly during the acquisition step.

With such a characteristic, the reference appliance that serves to perform the reference test for inspecting point-of-care biological test appliances also serves as an inspection appliance suitable for sending data to the centralizing system. Such an embodiment enables functions to be concentrated and combined within a single appliance.

According to another particular characteristic of the invention, the method includes a step of triggering a warning as a function of the content of the report received from the computer system.

Such a characteristic makes it possible to further automate inspection by giving the operator direct advice concerning the state of the point-of-care biological test appliance being inspected. The operator's own expertise then becomes a parameter that is of less importance than with prior art inspection methods. The report sent by the centralizing system then includes warning data which is subsequently interpreted by the inspection appliance or by the computer terminal that receives the report.

According to an advantageous characteristic, the comparison data associated with the qualitative data is stored in the form of a database.

Storing comparison data in association with qualitative data makes it possible to constitute a database that can be used subsequently for statistical evaluations or for subsequent determinations of a parameter, for example a bias that corresponds to some particular environmental situation.

In addition, organizing the data in the form of a database provides options concerning the traceability, the management, and the publication of data relating to inspecting point-of-care biological test appliances.

Several embodiments of the computer system can be envisaged.

It may be constituted by a single machine or by a plurality of machines interconnected by a network.

Thus, the method of the invention may operate in the form of a community of network services installed within a plurality of servers.

According to an advantageous characteristic, the method of the invention is suitable for operating in an initialization mode for the purpose of defining a bias for each point-of-care biological test appliance as a function of the control solution used, the bias being defined as being equal to the difference between the value of the variable as measured by the point-of-care biological test appliance and the value as measured by the reference appliance, or to the mean of said difference over a plurality of measurements performed by the point-of-care biological test appliance, with the bias being stored as part of the comparison data.

With such a characteristic, the comparison data then includes at least data concerning the bias that is to be expected as a function of the inspection situation, and thus as a function of the qualitative data, and of the point-of-care biological test appliance under consideration. Subsequent bias-determination steps make use of the stored comparison data. It should be observed at this point that the bias, which is defined for each appliance, may in fact be defined for each type of appliance and then attributed to all of the appliances of that type. It should also be observed that the bias, which may be a correction factor, is defined for each particular utilization situation of one or more appliances. To define biases, it is advantageous to make use of statistical analyses of the results in the database be peer group or by using any other type of criterion (method, appliance, etc.) that defines a particular situation.

In an implementation, the step of storing comparison data is performed only at the beginning of using and inspecting a point-of-care biological test appliance.

Such a characteristic enables the inspection method to be initialized progressively, in particular in terms of determining the bias. This amounts to a kind of training for the method that is to be used subsequently for later inspections.

Other means for defining biases can be implemented, in particular it is possible to define the expected target values and biases independently of the method of the invention before any use or inspection of the point-of-care biological test appliances and of the reference appliance. These target values and biases are then stored in the centralizing system before performing inspections. Naturally, the biases or correction factors and the target values need to be revised subsequently and regularly in order to avoid any drift and in order to detect any anomalies.

According to a particular characteristic of the invention, the qualitative data includes data qualifying the control solution.

The control solution may be selected from the following types of solution: a solution supplied by the manufacturer, the patient's blood, commercial total blood, or a so-called "universal" control solution. In this context, the term "universal" means that the measurement of the biological magnitude under test is substantially the same regardless of the biological test appliance used.

Such qualitative data makes it possible to define a bias for each control solution. Under such circumstances, during the bias-determination step, and when the "control solution" parameter is the only parameter used for determining the bias, the bias can be determined solely on the basis of knowledge of the qualitative data relating to the control solution. It will also be understood that the value of the bias will necessarily be different depending on the different control solutions that might be used. Incorporating data about the control solution within the qualitative data thus serves in particular to enable the bias to be determined more exactly.

Naturally, it can be envisaged that the parameter relating to the control solution is used in combination with other parameters involved in determining bias, for example the type of appliance, temperature, humidity, etc.

Depending on the application, the biological variable is selected from the following variables: glycemia, blood gas, hematocrit, lactates, urinary or blood ionogram, urinary glucose, creatinine, hemoglobin A1c, uric acid, cholesterol, triglycerides, or any other biological parameter, even if not known at present, providing point-of-care biological test appliances and an inspection appliance become available for performing the measurement.

The invention also provides an inspection appliance that can be used for implementing the method of the invention.

For this purpose, the inspection biological test appliance comprises: means for inputting or receiving qualitative data characterizing a point-of-care biological test appliance for inspection and characterizing the environment in which the appliance is to be found; means for inputting or receiving the value of a biological variable of a "control" solution as measured by the point-of-care biological test appliance for inspection; means for acquiring the value of the biological variable of the control solution as measured by a reference biological test appliance; and means for transmitting the input or received value, the measured value, and the input or received qualitative data to a centralizing computer system suitable for: determining a bias that is to be expected between the input or received value of the biological variable and the value as measured by the reference appliance, the expected bias being determined as a function of the input or received qualitative data, including data reporting on the environment in which the appliance is used, and of comparison data stored in the computer system; comparing the value as measured by the point-of-care biological test appliance with the value as measured by the reference appliance while taking the bias into account; storing the comparison data relating to the comparison performed, said comparison data being stored in association with the qualitative data; generating a inspection report; and sending the report to the inspection appliance or to a computer terminal associated with said inspection appliance.

In a particular embodiment, the inspection biological test appliance further comprises means for receiving the inspection report.

According to another particular characteristic of the invention, the inspection biological test appliance further comprises warning means triggered as a function of the content of the report.

The invention also provides a centralizing computer system suitable for communicating with a plurality of inspection biological test appliances of the invention.

For this purpose, the centralizing computer system comprises: means for receiving the value input to or received by the reference appliance, the value measured by a reference appliance, and the qualitative data transmitted by the inspection appliance; means for determining a bias that is to be expected between the input or received value of the biological variable and the value measured by the reference appliance, the expected bias being determined as a function of the input qualitative data and of comparison data stored in the computer system; means for comparing the value as measured by the point-of-care biological test appliance with the value as measured by the reference appliance while taking the bias into account; storage means for storing comparison data relating to the comparison performed; means for generating a inspection report; and transmission means for sending the inspection report to the inspection appliance or to a computer terminal associated with said inspection appliance.

In a preferred implementation, the various steps of the method are determined by computer program instructions.

Consequently, the invention also provides a computer program on a data medium, the program being suitable for being implemented in an inspection appliance suitable for communicating with a centralizing computer system of the invention, the program including instructions adapted to implement the following steps: inputting or receiving qualitative data characterizing a point-of-care biological test appliance for inspection; inputting or receiving the value of a biological variable of a "control" solution as measured by the point-of-care biological test appliance for inspection; acquiring the value of the biological variable of the control solution as measured by a reference biological test appliance; and transmitting the input value, the measured value, and input qualitative data to a centralizing computer system suitable for: determining a bias that is to be expected between the value of the input biological variable as measured by the point-of-care biological test appliance and the value as measured by the reference appliance, the expected bias being determined as a function of the input qualitative data and of comparison data stored in the computer system; comparing the value as measured by the point-of-care biological test appliance with the value as measured by the inspection appliance while taking the bias into account; storing the comparison data relating to the comparison performed, said comparison data being stored in association with the qualitative data; generating a inspection report; and sending the report to the inspection biological test appliance or to a computer terminal.

The invention also provides a computer program on a data medium, the program being suitable for being implemented in a centralizing computer system suitable for communicating with an inspection appliance of the invention, the program including instructions adapted to implement the following steps of: receiving the input value, the measured value, and the qualitative data transmitted by the inspection appliance; determining a bias that is to be expected between the input value of the biological variable after measurement by the point-of-care biological test appliance and the value as measured by the inspection appliance, the expected bias being determined as a function of the input qualitative data and of comparison data stored in the computer system; comparing the value as measured by the point-of-care biological test appliance with the value as measured by the inspection appliance, while taking the bias into account; storing comparison data relating to the comparison performed; generating a inspection report; and transmitting the inspection report to the inspection biological test appliance or to a computer terminal.

These programs may make use of any programming language and may be in the form of source code, object code, or code intermediate between source code and object code, such as in a partially-compiled form, or in any other desirable form, e.g. in an html code.

The invention also provides a data medium readable by an inspection appliance or a computer system, and including instructions of a computer program as mentioned above.

The data medium may be any entity or device capable of storing the program. For example, the medium may comprise storage means such as a read-only memory (ROM), e.g. a compact disk read-only memory (CD ROM) or a microelectronic circuit ROM, or indeed magnetic recording means, e.g. a floppy disk or a hard disk, means for optical or magneto-optical recording, random access memory (RAM), Flash memory, or any other medium for conveying a stream or for storing data, whether digital or otherwise.

Furthermore, the data medium may be a transmission medium such as an electrical or optical signal, suitable for being conveyed via an electrical or optical cable, by radio, or by other means. The program of the invention may in particular be downloaded from a network of the Internet type.

Alternatively, the data medium may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.

Brief description of the drawings

Other characteristics and advantages of the present invention appear from the following description given with reference to the accompanying drawings that show an embodiment having no limiting character. In the figures:

FIG. 1 is a diagram showing means for implementing a method of the invention;

FIG. 2 is a diagrammatic flow chart of a method of the invention;

FIG. 3 is a diagram showing a inspection appliance of the invention.

FIG. 4 is a diagram of a centralizing computer system; and

FIG. 5 is a diagram showing the presence of bias between measurements performed with point-of-care biological test appliances and the inspection appliance;

Detailed description of an embodiment

FIG. 1a is a diagram showing the implementation of a method in a first embodiment of the invention for inspecting a group of point-of-care biological test appliances 10, 11, 12, 13, and 14. These appliances 10, 11, 12, 13, and 14 are suitable for measuring a biological magnitude and for giving a value of this magnitude. For example, below it is assumed that the appliances 10, 11, 12, 13, and 14 are appliances for measuring glycemia that are designed to be made available to patients, for example in a plurality of rooms in hospitals or medicalized homes.

Nevertheless, the invention is not restricted to appliances placed at a patient's bedside, in particular in a hospital. The invention also applies to ambulatory appliances in a patient's home or in any location outside a laboratory, in particular in emergency vehicles (ambulances), in the premises of dispensaries, clinics, doctors' surgeries, etc. In this context, terms frequently used are "home tests" and "doctors tests".

Nor is the invention is limited to appliances for measuring glycemia, but it covers any appliance outside the laboratory for measuring by any single technique or combination of techniques for chemical, physical, physicochemical, optical, electronic, computer, or automatic measurement, or for measurement by new methods for the purpose of performing biological testing.

In the method of the invention, a first glycemia measurement QTD[i] of a control solution SC is performed with each point-of-care biological test appliance i, for i=10, 11, 12, 13, or 14.

The control solution SC may be total blood obtained by being taken from a capillary or a vein, a proprietary solution from an appliance manufacturer, or indeed a solution developed specially for checking the reliability of point-of-care biological test appliances. In any event, the control solution SC needs to be identical throughout the method of inspecting the reliability of point-of-care biological test appliances. It is also known that the term "control solution" can in reality cover the use of a plurality of solutions, each presenting a different level of the variable being measured. Thus, it is possible to use three solutions at low, medium, and high levels as a "control solution" SC. The principle of the invention nevertheless remains identical. Under such circumstances, each quantitative measurement corresponds to a triplet of values.

The values QTD[i] as measured by each of the point-of-care biological test appliances may be input into a personal digital assistant (PDA) 2, constituting the inspection appliance in this embodiment. A "reference" biological test appliance 3 also measures the value of the biological variable. The reference appliance 3 may also be referred to as a comparison appliance. The inspection appliance 2 is then suitable for acquiring the value as measured by the reference appliance. This acquisition is advantageously performed by the measured value being input to or received by the PDA 2. The PDA 2 is also suitable for transmitting data to a centralizing system 4 via a computer terminal installed in the laboratory or the service in which the point-of-care biological test appliances are inspected. This transmission also includes qualitative data QLD[i] also input to the PDA 2. These steps are similar to those mentioned in the following outline description of the preferred embodiment.

FIG. 1b is a diagram showing the implementation of a method in a preferred embodiment of the invention for inspecting a set of point-of-care biological test appliances 10, 11, 12, 13, and 14. These appliances 10, 11, 12, 13, and 14 are suitable for measuring a biological magnitude and for giving a value to said magnitude. By way of example, the appliances 10, 11, 12, 13, and 14 are appliances for measuring glycemia and they are designed to be made available to patients, e.g. in a plurality of rooms in hospitals or medicalized homes.

In the method of the invention, a first glycemia measurement QTD[i] is performed on a control solution SC by each point-of-care biological test appliance i, for i=10, 11, 12, 13, or 14.

FIG. 2 is a diagrammatic representation of a method of the invention.

By way of example, the values QTD[i] measured by each of the point-of-care biological test appliance are input into a PDA 2 for subsequent transmission to an "inspection" biological test appliance 3' in a step E0. Such transmission can be performed with the help of a wired or wireless connection depending on the technology selected from those known for transferring data from one electronic appliance to another.

It is also possible to envisage implementing the invention without using a PDA 2, which is thus shown in dashed lines. Under such circumstances, the point-of-care biological test appliances i may themselves include means for directly transmitting the measured values QTD[i] to the inspection appliance 3'. The inspection appliance 3' may also have input means to enable data to be input directly, including the values QTD[i] as measured by the point-of-care biological test appliances i.

FIG. 3 is a diagram of such an embodiment of a inspection appliance 3' of the invention. In this embodiment, the inspection appliance 3' includes a man-machine interface 31 including at least display means constituted by a screen 32 and input means constituted by a keypad 33.

Step E0 is thus a step of inputting or transmitting values for the biological variable as measured by the point-of-care biological test appliances i.

In the method of the invention, in a step E1, qualitative data QLD[i] is also provided before, after, or simultaneously with the transmission or the inputting of the values as measured on the point-of-care biological test appliances i. For this qualitative data, the same transmission or input means are used as are used for the quantitative data. The qualitative data QLD[i] identifies at least each of the point-of-care biological test appliances i for inspection. Thus, each value QTD[i] of the biological variable as input or transmitted is accompanied by at least one qualitative data item identifying the point-of-care biological test appliance i.

Examples of other types of qualitative data and of ways of encoding such data are given below.

Thereafter, in the preferred implementation, a step E2 is performed of measuring the value QTD.sub.CTL of the biological variable in the control solution SC by using the inspection appliance 3' which is specifically also the reference appliance.

For this purpose, and as shown diagrammatically in FIG. 3, the inspection appliance 3' includes measurement means 34. By way of example, these measurement means 34 operate on the basis of measurement reagent media, e.g. strips or wells on or in which a sample of the fluid for testing is deposited, here a sample of the control solution SC. The inspection appliance is thus constituted overall by measurement means, e.g. a photometer or an analyzer having analytic sensors, associated with a data input keypad.

The inspection appliance 3' then has the values QTD[i] as input or received corresponding to the measurements performed by the point-of-care biological test appliances, the measured value QTD.sub.CTL as measured by the inspection appliance, and also the qualitative data QLD[i] as input or received. By way of example, this data is stored in a memory 35 controlled by a microprocessor 36 within the inspection appliance 3' as shown in FIG. 3.

The inspection appliance 3' also has transmission and reception means 37 suitable for proceeding with a step E3 of transmitting data to a centralizing computer system 4. The system 4 may be implemented on a single machine or on a plurality of machines organized as a network. Communication between the inspection appliance 3' and the centralizing system 4 may be unidirectional or bidirectional.

As shown in FIG. 4, the computer system 4 comprises data transmission and reception means 43, data processor means 41, and received data storage means 42, at least. The storage means 42 are advantageously organized in the form of a database having fields that contain the qualitative data and that contain the quantitative data.

In an embodiment of the invention, the point-of-care biological test appliances are registered with the computer system 4 before performing any inspection. This registration may be performed automatically on the inspection appliance 3' suitable for performing the inspection requesting a subscription. The invention may thus be implemented in the form of a subscription to a network service that is accessible from inspection appliances, regardless of whether that appliance is the inspection appliance of the first embodiment or of the preferred embodiment. Either a local computer terminal to which the PDA 2 transmits the stored data, or the inspection appliance 3' itself therefore includes hardware and software means for communicating with the software means installed in the centralizing system 4 to which it is a subscriber. This subscription gives access to the database stored in the centralizing system 4.

The processor means 41 make use of the database to perform statistical processing on the qualitative and quantitative data received from the inspection appliance(s) 3'.

The centralizing computer system 4 may be in communication with a plurality of inspection appliances, e.g. situated in a plurality of services of a given hospital organization.

In particular, the data stored in the storage means 42 is used by the processor means 41 for evaluating the exactness of the measurements performed by the various point-of-care biological test appliances i.

This measurement accuracy is advantageously evaluated from the points of view of reproducibility and accuracy.

In order to inspect reproducibility, it is helpful to know a range of values within which the measured values QTD[i] are to be expected. This range, centered on a mean value, is typically defined with the help of a maximum departure from the mean ET[i].

Such a maximum departure from the mean ET[i] is generally a function of the type of point-of-care biological test appliance i that is in use and is common to all of the point-of-care biological test appliances of a given type.

In order to inspect accuracy, it is necessary also to know a possible bias B[i] that might exist between the value measured by each point-of-care biological test appliance i and the value QTD.sub.cm as measured by the inspection appliance 3'. The bias B[i] is a value that is expressed as an absolute value, and it is therefore positive. The bias B[i] may be added to or subtracted from the value QTD.sub.CTL measured on the inspection appliance 3'.

The term "bias" designates a numerical value or a mathematical function or a set of mathematical functions, that are calculated or described and that, when applied to the measured values, make it possible to write down a final inspection conclusion relating to the equipment being inspected.

This numerical value or this mathematical function or this set of mathematical functions, alone or in combination with one another, constitute a correction factor.

Such a correction factor serves in particular to enable a comparison to be made between a measurement made on total blood and a measurement made on plasma, or between a measurement of an element at one temperature and a measurement of an element at a different temperature, or under any other difference of environmental conditions such as humidity, atmospheric pressure, etc.

In any event, by taking account of the bias or the correction factor obtained by any appropriate method of calculation during the comparisons, it is possible to obtain a conclusion that is directly of use by the recipient of a inspection report without the recipient needing to take any account of a possible offset between measurements. In the meaning of the invention, the bias makes it possible to make two distinct data items comparable. Furthermore, the bias or correction factor can take account of a change of units between two data items.

The bias B[i] is advantageously defined as the difference between the true value VV of a sample and a single value QTD[i] or a mean of values QTD[i] as observed during a series of measurements on a single sample of the control solution. The true value VV may be defined absolutely when the solution comes from the manufacturer, or relatively as measured on the inspection appliance, or indeed on a laboratory appliance.

Under such circumstances, a bias is advantageously also defined for the inspection appliance by using the mean of the values QTD.sub.CTL obtained for a series of measurements.

In general, when the mean of the value QTD[i] is used, the bias can be expressed as a percentage using the following formula: bias in %=100*(mean QTD[i]-VV)/VV

It may also be calculated directly as a relative value: relative bias=mean QTD[i]-VV

It should be observed at this point that these percentage and relative biases can have values that are negative. In fact, when the bias is defined as being the absolute value of the bias, this leads to the bias being subtracted from or added to the target value. Naturally, such subtraction or addition may be preceded by multiplication when the bias is expressed as a percentage. The target value may be the true value VV when defined by using the inspection appliance 3'.

The bias is advantageously redefined on each change of batch of reaction media, on each change of reagent, on each change of the control solution, on each calibration, and on each change of appliance or type of appliance.

Knowledge of such a bias B[i] then makes it possible to automate inspection of point-of-care biological test appliances i since the processor means 41 are then in a position to compare the values QTD.sub.CTL measured by the inspection appliance 3 and by each of the point-of-care biological test appliances i.

For example, it is then possible to detect calibration that is inexact, maintenance that is inappropriate, and the use of reagents that is erroneous, or indeed poor conservation of reagents, or wrong use, or wrong setting of the appliances.

The description continues in the full USPTO document.